The performance of an investment is strongly related to execution costs related to the investment. Often with trading securities, transaction costs may be large enough to substantially reduce or even eliminate the return of an investment strategy. Therefore, achieving the most efficient order execution is a top priority for investment management firms around the globe. Moreover, the recent demand of some legislators and fund shareholder advocates of greater disclosure of commissions and other trading costs makes their importance even more pronounced (see, for example, Teitelbaum [14]). Therefore, understanding the determinants of transaction costs and measuring and estimating them are imperative. For further discussion see, for example, Domowitz, Glen and Madhavan [5] and Schwartz and Steil [13].
Traditionally, there appear to be two different approaches for estimating trading costs. The first approach is purely analytical and emphasizes mathematical/statistical models to forecast transaction costs. Typically, these models are based on theoretical factors/determinants of transaction costs and take into account, for instance, trade size and side, stock-specific characteristics (e.g., market cap, average daily trading volume, price, volatility, spread, bid/ask size, etc.), market and stock-specific momentum, trading strategy, and the type of the order (market, limit, cross, etc.).
The modeling is focused primarily on price impact and, sometimes, opportunity cost. For example, Chan and Lakonishok [4] report that institutional trading impact and trading cost are related to firm capitalization, relative decision size, identity of the management firm behind the trade and the degree of demand for immediacy. Keim and Madhavan [9] focus on institutional style and its impact on their trading costs. They show that trading costs increase with trading difficulty and depend on factors like investment styles, order submission strategies and exchange listing. Breen, Hodrick and Korajczyk [2] define price impact as the relative change in a firm's stock price associated with its observed net trading volume. They study the relation between this measure of price impact and a set of predetermined firm characteristics. Typically, some of these factors are then selected and implemented in mathematical or econometrical models that provide transaction cost estimates depending on different trade characteristics and investment style. ITG ACE™ (Agency Cost Estimator), described in [7] is an example of an econometric/mathematical model that is based on such theoretical determinants. It measures execution costs using the implementation shortfall approach discussed in Perold [12]. See also [15] and [16] for other examples of this type of model.
While the first approach implicitly assumes that past execution costs do not entirely reflect future costs, the second approach is specifically based on this principle. In the second approach, the focus is exclusively on the analysis of actual execution data, and resulting estimates are used primarily for post-trade analysis. Typically, executions are subdivided into segments called peer groups, then simple average estimates of transaction costs in each segment are built. Taking empirical averages, however, might cause problems. For example, very often cells with insufficient amount of data may provide inaccurate and inconsistent estimates due to just several outliers.
The present invention incorporates ideas of both approaches above to provide an improved method for estimating transaction costs.